Blood Stones:
It bloodstones were sealed with the blood of King Doric, hence the name bloodstone. The Bloodstones were broke to five pieces by the goda when they left Tyria, they dropped them into the volcanos in the Ring of Fire. Four of the Bloodstones are each sealed with a specific class of magic: preservation, destruction, aggression and denial, and the last piece is the keystone, without the ketstone, the four other will never be put together and unleash its unspeakable power. So far we have only found two Bloodstones; the one in the Wild and the one in the volcano, three still are missing. I think it is rather obvious that we will have to do something about the Bloodstones. Maybe we will have to return thewm back into the volcano; or maybe we will do something stupid and almost destroy the world. Who knows.
The Serpents:
The Serpents were created to guide the animals of Tyria while the gods were busy creating the world. the Serpents left when human dominated the world, they moved into the Crystal Desert. We never meet the Serpents in the current Crystal Desert. Perheps they will expand the Crystal Desert so we can meet the serpents to get help from them herheps.
The Charrs:
the Charrs were never mentioned later in the game. We never find out what happened to them and to Ascalon. Did they razed Ascalon to the ground after we left for Kryta? Are the Ascalonians still hanging on to the Northern Wall? And what about the Stormcaller, did it work? So many question still unanswered.
Well thats about all the possibel future updates I can think of.